Until it was replaced by the euro in 2002, the D-Mark (Deutsche Mark) was one of the world’s most stable currencies. In its short but eventful 54-year history, it was the official currency of West Germany and later the unified Germany. And then it was gone.

Is this the destiny of diesel? German. Stable. Gone.

Sure, history will note that Rudolf Diesel’s invention had a longer run. He filed a patent for an “internal-combustion engine” in 1895 in the US but it’s a safe bet that it is headed for the same fate as the D-Mark. Going, going…

Along with diesel fumes, fear was in the air yesterday in Berlin when German car executives and political leaders met to rescue Rudolf Diesel’s legacy. Their over-hyped meeting — dramatically described as a “diesel summit” — resulted in a plan to update the software in five million cars to reduce emissions of nitrogen oxides, the diesel by-product most harmful to human health. But it’s too little, too late. There’s a crisis of confidence in Germany’s most important industry. Volkswagen, Daimler and BMW are facing growing public anger at home and abroad for downplaying the health effects of diesel fumes and, in some cases, misleading customers about how much nitrogen oxides their cars produce.

The impact of all this on Germany cannot be overstated because vehicles are its single most important export product. They are also the most visible symbol of German engineering. Those arrays of BMWs, Mercedes-Benzes and Porsches are a source of national pride and (like the D-Mark once) a vital part of post-war German self-image. News that Volkswagen agreed to pay more than $22 billion in the United States in fines after admitting that it had programmed diesel cars to cheat on emissions tests rattled the country, and recent reports that Volkswagen, BMW and Daimler may have secretly agreed to cut corners on emissions hardware has created a feeling of betrayal.

France and Britain want to end the sale of diesel cars. Athens and Madrid are banning them entirely, but Germany is hanging on for dear life to its preferred fuel. It’s a risky strategy because hansom cab drivers didn’t see the automobile coming and the makers of the internal combustion engine might not hear the approaching electric car.